Japanese Patents Nos. 2,992,580 and 2,992,581 disclose a steel-framed building constructed by joining a column and a beam. However, these conventional techniques do not disclose that section steels having the same cross section are used for the column and the beam, the number of kinds of section steels to be used is undesirably increased, and building costs are increased. Further, a reinforcing member provided in a cross section of the beam constituting a beam-side joint and a reinforcing member provided in a cross section of the column constituting a column-side joint can not be formed as the same members. The number of kinds of reinforcing members to be used is undesirably increased, and building costs are increased.
Japanese Patent Application Laid-open No. H11-324129 discloses that a reinforcing member is joined to a cross section of a beam in a beam-side joint by a bolt. An end of a column is joined to a reinforcing member by a bolt, thereby employing a dry joint structure which does not need welding. However, this conventional technique does not disclose that the dry joint structure which need not be welded is employed in a column-side joint. Therefore, in the column-side joint, a horizontal stiffener is welded to the column, and the end of the beam is joined to the horizontal stiffener. The column may be bent due to thermal influence of the welding, and a special device such as an assembling jig is required for welding the stiffener.